The invention relates to joints, and more particularly to joints comprising particles that mechanically interlock adjoining surfaces.
It is well known in the mechanical arts that many methods are available to join or connect one part to another. These methods range from use of a chemical adhesive to welding.
Chemical adhesives generally adhere two surfaces by chemical interaction with the body materials. The joints can be of great strength and durability. The problem is that there are attendant environmental issues that arise with chemical adhesives, including storage, use and disposal of the adhesives. Further, they are often a health hazard to humans if used improperly. Chemical adhesives are primarily used on non-metallic materials, such as plastics and composites.
A welded joint is the primary means of joining metallic components. For example, electrical arc welding momentarily liquefies a portion of the bodies to be joined. The molten metal, in combination with metal from a welding rod, then solidifies to join the metallic bodies at a molecular level. The problem here is that some skill is required to weld properly. Further, high electrical currents, voltages and temperatures are necessary to liquefy the materials to be joined.
In addition to adhesives and welding, another xe2x80x98non-fastenerxe2x80x99 option is the galled joint. Galling is a process by which two bodies may be joined as a result of high levels of friction evenly disrupting the relevant surfaces causing controlled transfer of surface material from one body to another to produce an array of mechanically meshing recesses and protrusions that couple together and interlock to resist further lateral motion.
Representative of the art is U.S. Pat. No. 5,348,210 to Linzell(1994) which discloses a method of making galled joints by asperity deformation using a material between the members leading to welding on a molecular level but not sufficient to raise a temperature to a level where bulk welding will occur.
Also representative of the art is U.S. Pat. No. 5,837,066 to Linzell(1998) which discloses a method of making galled joints between two metal joints in which there are gaps prior to formation which comprises a composition comprises small metal particles combined with a gall enhancing material.
The galling method teaches use of a gall-enhancing material or composition that facilitates the galling process. The gall-enhancing material generally comprises a polysiloxane, which increases the friction between the members to be joined. Further, the joints rely upon a precise manner of combining the members to allow the galled joint to be properly formed, including controlling clearances, alignment and joint forming velocity. In addition, the joints disclosed in ""210 specifically teach against the use of grit in the joint. On the other hand, ""066 does teach the use of particles in the joint, however, the particles are used to promote galling between the surfaces and are used in concert with gall-enhancing material, namely polymethylsiloxane, to create a gall-enhancing composition. Also, the particles are generally equiaxed, meaning each is substantially the same in 3 dimensions, such as a sphere, or a cube or any irregular shape. This promotes joining of parts having substantially the same hardness, i.e., metal parts. However, the methods do not lend themselves to joining parts having a substantial difference in hardness, such as a plastic and metal. In particular, when one part is an elastomer, and the other part is metal, then the equiaxed particles can penetrate the relatively soft elastomer and disappear in them.
What is needed is a particle joint comprising particles that mechanically interlock adjoining surfaces. What is needed is a particle joint comprising particles having a substantially flat shape. The present invention meets these needs.
The primary aspect of the present invention is to provide a particle joint comprising particles that mechanically interlock adjoining surfaces.
Another aspect of the invention is to provide a particle joint comprising particles having a substantially flat shape.
Other aspects of the invention will be pointed out or made apparent by the following description of the invention and the accompanying drawings.
The invention comprises a joint formed by mechanical interaction of particles with the parts to be joined. The particles engage an interface surface of each part, creating a high friction condition that prevents further relative movement of the parts once they are assembled. The particles have a substantially flat or flake-like morphology. The surface of each particle is rough to enhance mechanical engagement with each interface surface. The flake-like shape prevents the particle from penetrating an elastomeric part, which would render the particle ineffective in the bonding process.